.224 load development help requested...Chrony Update

Taylor-Made

Taylor-Made

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Need some help guys,

I am trying to pick a load for my Rem 700 .223 with a 20" 1 in 9" twist. I am using Varget and 69 grain SMK loaded to 10 thou off the lands. This is my first load development and I am not sure how to pick my final charge weight. Yesterday it was dead calm at the range and I feel that although I am a new shooter I gave it a pretty consistent chance to group.

255g.jpg

Average of .588

256gr.jpg

Average of .471

257gr.jpg

Average of .544

258gr.jpg

Average of .425

259gr.jpg

Average of .525, Groups of .288 .472 and .815, however I believe the barrel was fouled as the groups fell off drastically. 25.9 had previously grouped well.



I had previously done some ladder testing but I only had 200 yards available to me and it proved tricky to decipher the results, however, I narrowed it down to the 25.5 - 25.9 range.

My first question is; Am I overly concerned with .1 grain increments. Secondly, what load would you go with and Thirdly, Is more range time required?

I am leaning towards 25.8 as it was the most consistent although I'm tempted to load some more at 25.9.

I apologize for rambling on like an idiot...But I can't help it because, well, I'm an idiot
 
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My advice is to go back to the range, and try the same loads, but shoot, say, 3 5 shot groups. 3 shot groups are good for zeroing your scope, a couple of 5 shot groups will give you a more consistant idea of how that particular load will actually shoot.
 
Try more 25.8. You should also keep track of atmospheric conditions when you test. If you can, do the next round of testing at 200 yards and your results will come a little clearer.

Ideally you need to be farther out to do a real ladder test. Most are done at 600 yards for LR rigs, for your 69's I would do no closer than 300-400 IMO

Also, pay attention to your shooting technique, a change in grip pressure, cheek pressure etc.. will skew your results. I have found this to be a cause, among other things, of those dreaded flyers.
 
Taylor-Made said:
My first question is; Am I overly concerned with .1 grain increments?
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Yes you are.
As mentioned, a three round 'group' pretty much tells you the mpi, and little else.

Taylor-Made said:
Secondly, what load would you go with and Thirdly, Is more range time required?
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I'd:
A) chrony your loads to arrive at a velocity you desire.
B) Load any of them, they are all doing the same thing.

Taylor-Made said:
I am leaning towards 25.8 as it was the most consistent although I'm tempted to load some more at 25.9.
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They are the same. You managed to do a bit better behind the trigger with 'one' than the 'other', but the reality is your powder charge measured a whopping 1% difference between 25.8 and 25.9 grains....if that is in fact the case - your scale likely has a variance of .1 grains or more...in which case they could very well be identical.

I would recommend spending more time working on consistant shooting than I would worrying about .1 grains this way or that.
 
Thx for the input guys...I think I'm going to make another range trip with a whole schwack of 25.6 .7 .8 .9 and as suggested shoot more groups from 200. Worst that could happen is I get more trigger time

Beltfed, you mentioned chrony until I find a speed I like...I have to ask, where do I come up with a speed I like (Bullet Manufacturer Maybe?)
Thx again guys
 
A chrony will give you a more precise measurement of your powder charge. Look for consistancy in speed. It will give you a better indication of your scale. Also, you mentioned a 10 thou "jump " to the lands. Once you get consistancy in your velocity, then start changing your distances to the lands. Every gun has a prefered "jump" to the lands. Some may like 2 thou while others might like a bigger "jump". Just make sure your OAL is above minimum. You didn't mention if you are crimping the bullet or not. Crimping improves the consistancy of your loads. Your mileage may vary.

-Jason
 
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  • It looks like you are shooting the rifle quite well.
  • All of these groups look quite good.
  • I can't see anything that would make me choose any group over the others (in the sense that they all seem about equally good)
  • Good for you for shooting three groups of each charge weight, and taking the average size of them. This gives reasonably useful data.
  • None of these groups show much vertical stringing. How variable was the wind you were shooting in?
  • Your choice of 0.1 grain increments was probably finer than necessary, particularly for your initial try with a particular bullet/powder combination, but certainly no harm done. Then again with something as common an as well-known as Varget plus 69SMK you get the benefit of lots of other peoples' experience before you
  • If you can chrono, try another 9-10 (either as three 3-shot groups, or two 5-shot groups, or one ten shot group) of 25.5 grain, and 25.7, and 25.9. See which of these, if any, seems to give more uniform velocities. If the 25.9 is more uniform than the other two, then continue to work up to hotter loads. If pressures are acceptable, you might find better accuracy and better velocity consistency at hotter loads.
  • If you are shooting out to 600, choose the most accurate load.
  • If you are shooting beyond 600, it starts to become very important to have good uniformity of velocity in order to avoid vertical stringing due to slower shots having more time to fall further. Definitely want an extreme spread in your velocities of no more than 50fps, and under 30fps is ideal.
  • If you have a bunch of equally-accurate loads, choose the one with least velocity variation.
 
rnbra-shooter said:
If you are shooting out to 600, choose the most accurate load.
If you are shooting beyond 600...
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Excellent point.

I see some guys on here and elsewhere develop loads they'll use at range, but don't shoot them beyond 100m during load development....

Point is to get out and shoot them...stretch their legs. That load that shoots like a house on fire at 100m may, however unlikely, sh!t the bed at 500.

Also, if you are planning on shooting that at longer ranges, the 69gr smk is not the best candidate for it.
 
IF your loads are perfectly metered and your AOL is consistant, there is still a small variance in your neck sizes (bullet not being held as tightly from one round to the next). If you don't crimp, try pulling on the bullet with your fingers. (You will be able to pull some of them out by hand :eek:.) By crimping your bullets, you eliminate this variable. Hope this helps.

-Jason
 
Tried the Chrony...Gonna start knitting instead

Well today I took my brand new shooting chrony to the range...I shot 10 of each 25.6,.7,.8,.9 grains....

It was cold and I'm a wimp so the targets which I had at 200 yards weren't great. I had intended to shoot 15 of each but I ran out of time. The chrony numbers weren't great either

25.6 - 2953 fps avg with an extreme spread (es) of 70 fps
25.7 - 2949 fps avg with es of 94 fps
25.8 - 2974 fps avg with es of 62 fps
25.9 - 2997 fps avg with es of 50 fps

I was surprised to see the amount of deviation. It was mentioned earlier that a 30 fps spread is ideal and I'm obviously not in the area

I'm hesitant to crimp as was suggested because I think it shortens case life....(I may be wrong?).

As I mentioned before trigger time is never bad and I do need the time to improve my skills, however, load wise where do I go now?
 
Taylor-Made said:
Well today I took my brand new shooting chrony to the range...
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I'm always nervous when I read stories that start out like that... glad to see that this wasn't one of those "I-shot-my-Chrony" ones...!

As I mentioned before trigger time is never bad and I do need the time to improve my skills, however, load wise where do I go now?
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Take a deep breath, and don't get disheartened. Now that your testing is getting more rigorous you are perhaps seeing things better, which at first glance usually seems pretty depressing.
  • Ten shot groups, on average, will tend to be about twice as large as three shot groups on average.
  • So all other things being equal, your half-inch-at-100 three shot groups would be one inch groups at 100.
  • Groups at 200 will be twice as large as groups at 100. So now you'd expect to see two inch ten-shot gropus at 200
  • All other things are not equal, and especially when using the usual way of measuring gropu size, the distance between the two furthest shots. This makes your measured group size particulary vulneable to a shooter error or an unusual wind fluctuation. You can fire nine out of ten shots well, but it's no problem at all for a poorly-fired tenth shot to turn a 2" group into a 3" group.

So that's how an honestly reported "half minute at 100" can easily turn into a very depressing "1.5 MOA at 200", without there actually being anything wrong with the rifle, ammo or shooter.

Observations on your results:
  • Generally your ESs seem to be shrinking as you go to hotter loads. As long as there is room for more powder and pressure signs are reasonable, it would be worthwhile increasing the charge weight in 0.1 grain steps, until either accuracy gets worse or velocity ESs (better yet, SDs) get worse.
  • Achieving an ES of 30fps (usually equivalent to an SD of 10fps) is very desirable, it is also not usually easy. There is a lot of good ammo out there with ESs of 50fps to 75fps. High quality commercial match ammo (Federal Gold Medal Match etc) typically have SDs in the high teens or low twenties, which is an ES of 60-ish. Realize that the goal of a 30fps ES is for world-match-winning ammo; don't think you're a bad reloader if it takes you several tries to achieve that (!).
  • You're probably at the stage of load development now that you should start paying attention to some of the smaller details, if you aren't already doing so. At least for load development purposes, each of your charges should be weighed to be within the 0.1 grain increment that you desire. Your bullet runout should be measured and it should be reasonably good (no more than three or four thou of total indicated runout, hopefully less). Your bullet pull should be fairly consistent (clean any case lube from inside of necks)
  • Once you've established the "map" of ESs and accuracy for your accurately-weighed charges with consistent neck tension, you might try some crimping of the bullet. This is a trick that sometimes improves the uniformity of the burn (and sometimes not). But this is not something that you necessarily must try, think of it as one of the second-order tools that a reloader has at his disposal to try.
  • Other comparable second-order-tuning-changes you might make are to try significantly less (but uniform) neck tension; to load the bullet with a lot more jump; to load the bullet right up against the lands, or even well into the lands (e.g. 20 thou).
  • Or since your Varget/69SMK combo may well be "bulked-out" for powder space, trying a slightly quicker powder might be worthwhile (trying H4895 sort of jumps out at me).

Do realize that things are probably going a lot better for you than they actually feel/look! ;-)
 
Great Feedback Daniel. My biggest concern was the ES numbers. I wasn't aware that 30 fps is considered very good and that my 50 wasn't all that bad. Well back to the loading room for another trip to the range :)

Thank-you again
 
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I do measure each charge of powder so I am confident that my weights are correct, however, neck tension is something I never considered.

The brass I am using is "Lake City" and I had read on 6mm benchrest that it is a fairly good brass. Another thought that came to mind is I may not have uniform case capacity. With the exception of actually tracking individual cases through the chrony is there an easy way to weed out the non uniform cases?

Getting tired of me yet?

Thank-you again
 
Like Jason said, weigh your brass and set aside any obvious outliers (weighing doesn't *actually* measure case volume, but it's a fairly good proxy, even moreso when you are dealing with the same maker and batch of brass).

Try to have all the pieces of brass in each ammo box you own, weigh within a 1 grain band (there's no need to sort into 0.1 grain "bins"!). Then, treat each box of brass as a group. Load it all, then don't reload any of the brass in there until you've fired them all. Put a piece of tape on the side of the box, and add a tick mark every time you reload the box. Every time you trim (and then chamfer the mouth!), mark a tick in another place. You might want to keep track also of how many times you have FL sized the brass (if you sometimes FL size and sometime neck size; the can help you connect how many sizings you get between trimmings). If a piece of brass gets lost, or if you ruin it and have to throw it out (e.g. an overpressure load loosened a primer pocket), throw it out and leave its spot in the box empty. In this way, you can keep track of the brass through its life.

Keep one box for your obvious outliers. Don't shoot with it in anything important. But you can do interesting experiments with it. For example, record your very heaviest and very lightest piece of brass that you own. One you have a really good load worked out, load up some of your good brass with that load, and also load up your "outlier heaviest" and "outlier lightest" piece with the same load. When you are next testing your ammo at the range under good conditions and you are shooting well, fire a group (five or ten shots) with your good ammo, ideally over a chronograph. Then, fire one shot of your "outlier-heaviest", and see where it goes in the group and what its velocity was. Then do the same thing with your "outlier-lightest". Doing this can give you a good handle on how much effect the "very worst" situation might have. If for example the bullets from these outliers go right into the group (which is what will usually happen), you have some concrete proof in front of your eyes that sorting brass makes little to no difference in your group sizes. If you know this, then you can be "intelligently lazy" in your future loading and future brass prep. If the velocity of these "outliers" falls within the spread of your sorted brass, that's another useful thing to know for The Lazy Man Precision Loader. And if its velocity is outside the range, not only does that tell you that your effort in sorting your brass is useful, it also gives you an idea of how big the effect might be (e.g. "X" fps per 0.1 grain of brass weight change) - this you can use to make other decisision, for example "I don't need to weight sort my brass for 0-600 yard ammo, but I *do* need to sort it for my 1000 yard ammo otherwise I might see a difference of (for example) 20 inches vertical impact on the target".

Other useful tests of your "outliers" that you can do - if you ever damage the tip or base of a bullet, or if you scratch it up quite badly while seating and extracting it, load these into your good brass with your known-good load (mark them of course) and then test them in the same manner as you test the other "outliers". It can be reassuring to know that such-and-such damage does (or does not) go into the same hole as an undamaged bullet.
 
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